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The BMW M4 GTS is more than just a high-performance sports car for the road with a penchant for unfurling maximum power on the race track; in its ingenious water injection system, the BMW engineers have conjured up a technical masterpiece.

By
Michael Seitz

BMW M drivers are a dynamic bunch – engine power in spades, the feeling of speed through corners and supreme sports performance are the pillars on which their world resides. At the smouldering core of this red-hot collective are high-performance special-edition models. Those who pilot these ultra-dynamic cars can be considered expert exponents of the driving art – and often line up at clubsport races to prove it.

In this rarefied arena, only a BMW with competition-spec performance will cut the mustard for the drivers. And it should be one they can drive to the track as well as on it. Limited-run special-edition models have a long tradition at BMW M: from the legendary E30 BMW M3 Evo in the 1980s via the 1990s BMW M3 GT Coupé (E36) to 2003’s BMW M3 CSL (E46). What they all have in common is their status as the shortest crossing point between the race track and the road.

And now here we are again. In spring 2016, Plant Munich will begin production of the BMW M4 GTS in a limited run of 700 units. As in the past, seasoned BMW M engineers have optimised all the relevant areas and dozens of individual components to equip the car for the exacting environment of race action.

The fastest lap set by the BMW M4 GTS on the legendary Nürburgring-Nordschleife circuit is 7 minutes 28 seconds. That makes this one of the fastest road-legal supercars around.

The BMW M carbon bucket seats don’t just look sporty in the extreme, they also lower the car’s centre of gravity and offer flawless lateral support at the ragged edge.

Here, the engine developers have pulled off an extraordinary coup. The BMW six-cylinder in-line engine with BMW M TwinPower Turbo technology already gives the standard M4 a high-revving capability well beyond the turbocharged norm – not to mention a weighty slug of torque.

However, the unit under the bonnet of the BMW M4 GTS is the first series-produced BMW engine to feature an astonishingly effective water injection system. Water is injected as a fine spray into the intake manifold’s plenum chamber where it evaporates, lowering the temperature of the intake air by around 25°C. This reduces the potential for uncontrolled combustion in the cylinders and allows higher boost pressure and therefore increased output (500 hp) and torque (600 Newton metres). As well as increasing the engine’s effectiveness, the cooled air prevents many components from overheating – and this, in turn, reduces fuel consumption under heavy loads.

The end result is that the BMW M4 GTS sprints from 0 to 100 km/h in 3.8 seconds. The weight of the five-litre water tank sits over the rear axle – to good dynamic effect. Under normal driving conditions, the driver will need to top up with distilled water at roughly every fifth refuelling stop. The frequency increases, of course, on the race track. But, as product manager Christoph Smieskol points out: “If you’re pushing hard on a circuit, you’ll be stopping for fuel before you need to fill up with water.”

The commitment to weight saving extends to the interior door panels and rear side trim, which are made from an ultra-lightweight material gleaned from renewable sources. Pull loops in the doors replace the usual handles.

0 to 100 km/h in 3.8 seconds: impressive performance, thanks in part to the water injection system fitted for the first time in a series-produced BMW. By cooling the combustion air, this technology enhances the effectiveness of the engine. At the same time, the thermal loads on the engine’s constituent parts are reduced.

0 to 100 km/h in 3.8 seconds: impressive performance, thanks in part to the water injection system fitted for the first time in a series-produced BMW. By cooling the combustion air, this technology enhances the effectiveness of the engine. At the same time, the thermal loads on the engine’s constituent parts are reduced.

As well as optimising the engine, the BMW M engineers have also made improvements to all the other components of the BMW M4 GTS involved in maximising performance on the race track. Key elements have been touched by the wand of lightweight design: the roof, bonnet, boot lid, adjustable rear wing and front splitter are all made from carbon-fibre. The interior is likewise the scene of weight savings; the M carbon bucket seats are a good example, as are the lightweight door panels fitted with pull loops instead of the usual handles, the material for which has been gleaned from renewable sources.

The weight-loss programme and increase in rigidity make their presence felt even more clearly in the adjustable BMW M coilover suspension, which features mechanically adjustable compression and rebound settings and can therefore be customised to the characteristics of different tracks.

Whenever talk in the BMW M community turns to the race track, mention of the legendary Nürburgring-Nordschleife is never far away. The unique challenge of this 20.83-kilometre-long exploration of camber and gradient is anchored in the genes of each and every BMW M car. The BMW development engineers have always come here to test their new models, and BMW was the first manufacturer to set up its own test centre at the circuit in 1992. In these circles, a quick lap around the ’Ring is considered a credible barometer of sports performance. The fastest time recorded so far in the BMW M4 GTS (set by BMW M chassis engineer Jörg Weidinger) is 7 minutes 28 seconds. And that makes this one of the fastest road-legal super-sports cars in the business – after a single timed Nordschleife lap. Weidinger sees room for improvement: “In several places I had to correct my line. So there’s still time to be shaved.”

The BMW M4 GTS raises the bar in terms of both engine development and lightweight design. OLED technology makes its debut in the rear lights, providing the car with a spectacular showcase.

Model facts

BMW M4 GTS

Displacement cc
Cylinders

2979
6

Output
kW (hp)


368 (500)

Torque Nm

600

Top speed km/h

305

Acceleration
0–100 km/h in s

3,8

Fuel Economy (EU)
l/100 km
urban
inter-urban
combined



11,2
7,0
8,5

CO2 emissions
g/km


199

Energy efficiency rating

E

01/22/2016